Brush material and brushes made therefrom



June 13, 1950 R. o. PETERSON BRUSH MATERIAL AND BRUSHES MADE THEREFROM Filed Dec. 13, 1945 INVENTOR.

RUBEN O.PETERSON 06W, EW V90 ATTORNEYS Patented June 13, 1950 UNITED STATES PATENT OFFICE BRUSH MATERIAL AND BRUSHES MADE THEREFR-OM Application December 13, 1943, Serial No. 514,649

4 Claims.

The present improvements, relating as indicated to brush material and brushes made therefrom, have more particular regard to the utilization in brush manufacture of filaments made from a. synthetic plastic. Certain types of brushes, e. g. tooth brushes, have been successfully made from one or more of the synthetic plastic compounds which are at present commercially available. However, the utilization of such material to make a satisfactory brush on the order of a paint brush has presented a much more difiicult problem and that so far as I am aware has never been satisfactorily solved. As is well known, paint brushes of the better grade are made of animal bristles which have certain characteristics of form and structure which it has thus far been found impossible to duplicate in the artificial filament irrespective of the synthetic plastic of which the filament is formed. Thus such animal bristles, aside from their inherent fiexibility, have a natural tendency to lay together, due to their form lend themselves readily to the formation of a layer wherein the ends of the component filaments contact with each other, and such ends furthermore are sub-divided into a socalled fiag which materially assists the brush to hold the liquid, such as paint, and distribute the same evenly over the surface as the edge of the brush is drawn in contact therewith.

One principal object of the present invention I is to duplicate in a brush composed of filaments made of synthetic plastic material the foregoing characteristics which are desirable in various types of brushes and not merely in the paint brushes specifically alluded to. A further object of the invention is to provide filaments of synthetic plastic material which are adapted for use in the manufacture of strip brush elements wherein the brush material is doubled upon itself and held in a channel-form base. Elements of this type are finding an increasinglywide field of use not only in the construction of fiat but also of circular and cylindrical brushes, but the manufacture of such brush strip elements, utilizing animal bristles, has never been satisfactorily achieved.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawing and the following description set forth in detail one method and one product exemplifying my invention, such disclosed procedure and product consisting, however, of but one of various applications of the principle of my invention.

In said annexed drawing:

Fig. l is a more or less diagrammatic representation of a strand or filament, made from a synthetic plastic material, such as I utilize as the basis for my improved brush material and the manufacture of brushes therefrom;

Fig. 2 is a diagrammatic representation of one step in the treatment of such stranded or filamentous material preparatory to thus utilizing it in brushes;

Fig. 3 illustrates likewise more Or less diagrammatically an individual component of my improved brush material as it appears in a finished brush;

Fig. 4 is a perspective view illustrating the manner in which filaments of the type in question are assembled in the making of a brush strip;

Fig. 5 is a perspective view of the finished strip resulting from the operation thus illustrated in Fig. 4; and

Fig. 6 is a diagrammatic view illustrating a further step in the treatment of the brush material which enters into the construction of such brush strip or other form of brush.

Various synthetic plastic compounds are commercially available which are capable of being formed into filaments of any degree of fineness and a large field of use for such filaments in the form of fibers has been developed in the manuiacture of textile goods. To be suitable for use in brush manufacture the filaments will ordinarily require to be of substantially greater diameter than in the making of such fibrous material; furthermore, other qualities required in brush materials, not only mechanical but thermal and chemical, will determine the selection of the particular synthetic plastic. I have found that synthetic fiber-forming polymeric amides which have a protein-like chemical structure are particularly well adapted for use as a substitute for bristles in the manufacture of various types of brushes. However, the present improvements are not limited to the employment of this particular kind of synthetic plastic.

A distinctive feature of the filament employed in my present improved brush material, as illustrated in Fig. 1, is that it comprises successive portions 9 and 2 which differ substantially in diameter, the portions of larger diameter being connected with those of smaller diameter by intermediate tapering portions '3. it will be understood that the relative lengths of the portions 1, 2 and 3 may vary, depending upon the characteristics which are desired in the finished brush material. It will also be understood that the diameters of the successive portions I and 2, both actual and relative, may similarly be varied. By way of illustration, for use as paint brush material such larger diameter may be on the order of twelve thousandths (0.012) of an inch and the smaller diameter on the order of eight thousandths (0.008) of an inch.

To form the brush layer a continuous strand or filament such as illustrated in Fig. 1 is cut into lengths which will consist of one of the portions of larger diameter tapering at its respective ends to the portions of smaller diameter.

This is conveniently effected by bisecting the .may be heated or heat otherwise applied to the material as it is passed therebetween. In the brush material composed of filaments thus formed, individual filaments are doubled upon themselves at points approximately midway of their portions I of larger diameter. the individual filament S, as indicated in Fig. 3, actually constitutes two brush strands each of which tapers from the doubled portion or base towards its outer end.

The manner in which my improved brush material is made into a brush strip is illustrated in Fig. 4. As there shown, a layer of filaments S is placed transversely of a strip 1 preferably of metal, which has struck-up along its respective edges a series of teeth or projections 8. A wire 9 or equivalent elongated retaining member is then disposed over such layer of brush material, preferably along median line of the strip 1, and the latter is bent up into channel form so as to cause the teeth or projections 8 to overlap and lock in place the retaining member 9 with the component strands of the brush material doubled thereabout.

In depositing the layer of brush material on the strip 1 the component strands will preferably, although not necessarily, project an equal distance beyond each side of such strip so that when thus doubled, following the formation of the strip into a channel, the ends will lie not only parallel with each other but project an equal distance above the channel base. The resultant brush element in the form of a brush strip B will have the general appearance illustrated in Fig. 5. It may be of any length and instead of the base being straight as illustrated, such base may be curved to form a circular brush or be wound helically to form a cylindrical brush.

Incidentally to the formation of the brush element as illustrated in Fig. 4, following deposit of the layer of brush material on the strip 1 and of the retaining member 9 on top of such layer, an agent capable of acting on the plastic material whereof the strands or filaments are composed to cause such material to coalesce or adhere, is desirably applied to the portions or strands of the filament that are doubled about the wire. The selection of the particular agent will of course be determined by the particular synthetic plastic employed to make the original filament. Where the latter is a polymeric amide such as referred to above, I have found that ortho-hydroxy-diphenyl will serve satisfactorily,

Accordingly the desired action occurring upon application of a certain degree of heat to the base of the finished brush strip.

The action of the agent named as suitable for use in setting the brush material in the channel base is understood to be that of a solvent, and the amount used will be suflicient merely to superficially soften the portions of the filaments which compose the brush material wherewith such agent comes in contact. The temperature employed to render the agent effective will be one somewhat above its melting point but well below any temperature at which the synthetic plastic compound which forms the brush material will be affected.

A preferred method of applying the agent to the base portions of the filaments is to impregnate a tape of fiber or equivalent material with the agent and then interpose such tape between the strip from which the channel base is formed and the layer of brush material, in the same manner in which the tape or band of plastic ma-- terial is employed in my Patent No. 2,303,386 dated December 1, 1942. such impregnated tape will be of the proper width to fit between the two upstanding rows of teeth or projections 8 on the strip and will be folded around the looped or doubled portions of the bristle material when the strip is given its final channel form. Thereupon heat is applied to the base of the resulting brush strip by any suitable means which will bring the impregnating agent to a temperature where it will act on the synthetic plastic compound whereof the brush material is composed.

A final step in the treatment of my improved brush material, particularly when assembled in the form of a brush strip as illustrated in Fig. 5, consists in roughening the lateral surfaces of the end portions of the individual strands. This may be very satisfactorily accomplished by use of the device illustrated in Fig. 6. Such device comprises a rotary abrasive member I 0 of general helical form towards which the brush element B is approached with its outer or free edge parallel with the axis of such member until the latter engages the end portions of the component strands or filaments to such extent as may be desired. The position of the brush element may, however, be reversed to insure the contact between the abrasive member and such end portions of the strands on all sides of the latter, and, if desired, the brush strip may be moved in a direction parallel with the axis of the abrasive member. In any event, the latter will act on the end portions of the strands both in a crosswise and longitudinal direction, with the result that the taper of such portions is further increased and at the same time the surface left in a roughened state.

Brushes constructed as hereinbefore described have been found to have substantially all the desirable qualities of similar brushes made from the best grade of animal bristles. In addition, owing to the fact that the filaments which enter into the present improved construction are oppositely tapered and doubled at the point where they are retained in the channel back or equivalent holding member, it is rendered possible to secure the brush material with a degree of permanence not possible in the use of animal bristles.

While I have named, by way of example, only one specific synthetic plastic compound, viz. fiber-forming polymeric amides, it will be understood that my present improved brush material may be made from other compounds similarly utilizable in the manufacture of synthetic fibers, such as are listed in the current Plastics Catalog published by Plastics Catalog Corp. of New York, N. Y.

It should be further noted that the hereinbefore described method of crimping filaments of synthetic fiber-forming plastic material may be advantageously employed in conditioning such brush material irrespective of whether the filaments are taper-ed or not. In other words by simultaneously applying heat to the filaments as they pass between the crimping rolls diagrammatically illustrated in Fig. 2, not only will the resulting crinkled effect be made permanent but the strains imparted to the filaments by previously performed operations will be relieved. Accordingly such crimping step, combined with heating, may be advantageously employed in conditioning straight filamentous brush material. The use of crimped or crinkled material in rotary brushes designed for polishing, cleaning and like harsh operations has the important advantage that fluttering is substantially eliminated. The flutter that develops in brushes made of noncrimped material, when the brush is rotated at high speed, is so pronounced as greatly to increase the power required and also makes it almost impossible to apply compounds to the brush or accomplish a uniform finish.

As best shown in Fig. 3, the crimping or crinkling of the filaments which constitute the stranded brush material preferably begins at the base of the component strands, i e. adjacent the doubled portions thereof, but terminates at a point a substantial distance short of the outer ends of such filaments or strands. On the other hand, such end portions, which taper as described, will desirably be subjected to the roughening action of an abrasive member as hereinbefore described.

The temperature employed in the crimping operation will vary of course with the particular plastic composition whereof the filaments are made. In the case of the composition referred to above it has been found satisfactory to maintain the crimping rolls at, or slightly above, the temperature of boiling water.

Other forms may be employed embodying the features of my invention instead of the one here explained, change being made in the form or construction, provided the elements stated by any of the following claims or the equivalent of such stated elements be employed, whether produced by my preferred method or by others embodying steps equivalent to those stated in the following claims.

I therefore particularly point out and distinctly claim as my invention:

1. A brush element comprising a channel, a retaining member disposed lengthwise thereof, and brush material held in said channel by said member, said brush material comprising a plurality of filaments of synthetic fiber-forming material doubled about said member and projecting beyond said channel, the projecting portions of said filaments tapering from the doubled. portions towards the ends thereof, and each having successive portions crimped in different angularly related planes.

2. As a new article of manufacture, a brush comprising a brush back and synthetic bristles extending therefrom, said bristles each having successive portions crimped in different angularly related planes.

3. As a new article of manufacture, a brush comprising a brush back and synthetic bristles extending therefrom, said bristles tapering towards their outer ends and each having successive portions crimped in different angularly related planes.

4. As a new article of manufacture, a rotary brush comprising a brush back and synthetic bristles extending substantially radially therefrom, said bristles each having successive portions crimped in different angularly related planes.

RUBEN O. PETERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 424,763 Cunningham Apr. 1, 1890 1,178,179 Rasmesen, Jr Apr. 4, 1916 1,238,635 Chandler et a1 Aug. 28, 1917 1,493,670 Galvin May 13, 1924 1,627,704 Izawa May 10, 1927 1,869,102 Herold July 26, 1932 2,227,126 Cooke Dec. 31, 1940 2,288,337 Whittle June 30, 1942 2,292,905 Smith Aug. 11, 1942 2,294,957 Caldwell Sept. 8, 1942 2,300,791 Lodge Nov. 3, 1942 2,303,800 Swann Dec. 1, 1942 2,317,485 Rider Apr. 27, 1943 2,326,174 Rutishauser Aug. 10, 1943 FOREIGN PATENTS Number Country Date 269,783 Italy Dec. 3, 1929 

1. A BRUSH ELEMENT COMPRISING A CHANNEL, A RETAINING MEMBER DISPOSED LENGTHWISE THEREOF, AND BRUSH MATERIAL HELD IN SAID CHANNEL BY SAID MEMBER, SAID BRUSH MATERIAL COMPRISING A PLURALITY OF FILAMENTS OF SYNTHETIC FIBER-FORMING MATERIAL DOUBLED ABOUT SAID MEMBER AND PROJECTING BEYOND SAID CHANNEL, THE PROJECTING PORTIONS OF SAID FILAMENTS TAPERING FROM THE DOUBLED POR- 